Luminous tube



March 15, 1932. A QTERO 3,34%,469

LUMINOUS TUBE Filed June 20, 1929 2 Sheets-Sheet l INVENTOR J 0279 0ATTORNEY March 15, 1932.

J. A. OTERO 1,849,469

LUMINOUS TUBE Filed June 20, 1929 2 Sheets-Sheet 2 INVENTOR I H /fera BYWWW A TTORNEY Patented Mar. 15, 1932 JUAN ANTONIO OTERO, OF LA PLATA,ARGENTINA LUMINOUS TUBE Application filed June 20,1929, Serial Na.872,390, and in Argentina August 20, 1928.

This invention relates to glass tubes, either clear, opaque, colored orotherwise, having in their interior a tungsten or other metallicfilament conveniently extended therethrough and held in place in thecentre of the tube in which a vacuum is afterwards producedor an inertgas is introduced under a low pressure.

The principal difficulty up to the present has consisted in maintainingthe metallic fila-. ment extended in the centre of the tube and properlyinsulated so as not to touch the inner Walls of the same. 7

According to the present invention this difiiculty is overcome in themanner hereinafter described with reference to the accompanyingdrawings, in which Fig. 1 is a plan View of a strip of mica with ametallic filament threaded therethrough; Fig. 2 is a cross section ofthe same; Fig. 3 is a sectional view of a tube with the said mica stripand metallic filament inserted therein; Fig. 4 is a representation of afragment of seven divisions, (say of one meter each) of a tube of tenmeters in length, showing the connections from the tungsten filament,through the glass tube, to the main conductors or leads H; Fig. 5 is aletter M formed of a tube four divi sions (or meters) in length; andFigs. 6, 7, 8

and 9 are modified forms.

Referring to the said drawings, A is a mica strip with a series of openspaces of uniform size, and which, as shown, has the aspect of a ladderto support the filament.

In the centre of each round of the ladder there is a small perforationthrough which to pass the metallic filament. The width of the mica stripwill vary according to the size of the tube to be used, and this sizemust be sufficient to facilitate its being passed through the tube withthe least possible play after being placed in its proper location. Thefilament may also be held in place by means of hollow glass beads,either cylindrical or spherical, or by mica rings, through which thefilament is threaded.

At the ends of the metallic filaments pieces of platinum or copper wireare provided which can be imbedded in the glass for the exteriorconnections.

The tubes provided with the strip or rings of mica may be curved withthe strip, rings, etc., and the filament inside, while those havingglass beads may be bent first and the filament with the beads introducedafterwards. 5:5

Using tungsten wire five one-hundredths of a millimetre in diameter, thetubes may be constructed, say of one meter in length, to be adapted to220 volts direct or alternating current (D, Fig. 3), although singlefilament tubes may be made of any length. The intensity of the lightbeing in proportion to the diameter of the filament utilized, with afilament of greater diameter a stronger light will, of course, beproduced, and it is obvious that the points of connection to theexterior maybe further between on account of the lesser resistance ofthe thicker filament.

The letter F, (Fig. 3) shows a tube, being a fragment of a tube of tenmetres in length, with its filament running through its entire length,and in it there may be seen at each meter a connecting wire of boraciccopper extending outwardly through the tube. These connections to theexterior may be eleven in number, for example, the even numbers beingconnected to one lead of the supply line, and the odd ones to the other,so that between each two adjacent connection points the 220 volts of theleads pass, and thus on through the succeeding connections they areconnected 'in quantity or parallel to the lighting circuit.

These tubes, before the formation of the vacuum therein, may be bent inthe lamps or given the form of letters for luminous signs and the like,after which the vacuum is produced.

Figs. 6, 7 8 and 9 represent sections of tubes in which there may beseen the form in which the metallic filament is supported; Figure 6being a tube G in which the filament B is held by the mica strip A; Fig.7 a similar representation of a tube in which the filament is supportedby glass beads J; Fig. 8 being another section of tube G in which thefilament is' supported by mica rings or disks L, which in their turn areheld by the hollow glass beads J and Fig. 9 is a W9 section of a lasstube G in which the-filament B is hel in place by mica rings K.

Fig. is a representation of a large letter M formed of a tube of theclass described. The outlets designated by the numbers 1,

3 and 5 are connected to one line of the circuit and the outlets 2 and 4to the other.

The attractive and fancy luminous letters and designs made with thesetubes have the advantage of economy, facility of formation and freedomfrom danger.

The tubes of this kind may be operated on the ordinary 220 or 110 volt"distribution cir cuits, since by merely varying the distance between thecontact points they may be adapted to any availab e voltage, thus doingawa with the necessity for transformers for ro ucing the high tensioncurrent which is indispensable in the use of luminous tubes of the usualtypes usin rarefied gases.

It is understood that the forms of the invention described andillustrated are merely illustrative, and that changes of the details ofconstruction which n'aturall occur to those skilled in the art, will notepart from the spirit of the invention, as set forth in the ap endedclaims.

aving described my invention, what I claim and desire to protect-byLetters Patent of the United States of America, is:

l. A lamp tube having a filament su port consisting of a mica tape havinholes t erein, a metallic filament threade therein and spaced from thewalls of said tube.

2. A lamp tube having a filament support consisting of mica rings havingholes therei in, a metallic filament threaded therein and spaced fromthe walls of said tube.

Signed at Buenos Aires, Argentine Republic, May 24, A. D. 1929.

JUAN ANTONIO OTERO.

